Method and structure for reclosable containers



ea. 13, 1966 KAKUJI NAITO L METHOD AND STRUCTURE FOR RECLUSABLECONTAINERS 3 Sheets-Sheet 1 Original Filed Feb. 15, 1961 Dec. 13, 1956KAKUJI TQ 3,29fifi??? METHOD AND STRUCTURE FOR RECLOSABLE CONTAINERSOriginal Filed Feb. 15, 1961 5 heets-Sheet 2 [YVEIYZUF 557% Elf/y 5.

Dec. 13, 1966 KAKUJI rro 3,29Lfl7? METHOD AND STRUCTURE FOR RECLOSABLECONTAINERS Original Filed Feb. 15, 1961 3 Sheets-Sheet 5 52 44 aan fijjUnited States Patent M 3,291,177 METHOD AND STRUCTURE FOR RECLOSABLECONTAINERS Kaknji Naito, Kawasaki-ski, Japan, assignor to KabushiiriKaisha Seisan Nikon Sha, Tokyo, Japan, a corporation of JapanApplication Oct. 23, 1963, Ser. No. 325,197, new Patent No. 3,246,672,which is a division of application Ser. No. 89,540, Feb. 15, 1961.Divided and this application Nov. 17, 1965, Ser. No. 508,270

Claims priority, application Japan, Apr. 11, 1960, 35/21,148, 35/21,149;June 3, 1960, 35/26,770 6 Claims. (Cl. 150-3) This application is adivision of application Serial Number 325,197, filed October 23, 1963,now Patent Number 3,246,672, which is a division of application number89,540, filed February 15, 1961.

This invention relates to bags made of synthetic resin, wherein havebeen formed integral with the bag material at the inner surface of thebag mouth vis-a-vis each other, a male rib and a female rib which areprovided as to be occlusive with respect to each other.

In making the tubular bag material, the bag material is molded into along continuous tube, which is obtained by extruding from a conventionalextruder a synthetic resin under heated state upward through an annularextrusion gap to form continuously a tubular body in which are formed bymeans of incision-like molding grooves provided in a section of theannular extrusion gap simultaneously in the inner surface thereof raisedmale and female ribs parallel with the line of generation of the tubularbody. Then, in transporting this while clasped in a state of flatness bymeans of a pair of rolls provided at the top of the apparatus, air isfirst blown from the aforesaid molding mold into the tubular bag body tomaintain the same in a swelled state between the mold and the aforesaidrolls and by concurrently blowing in cold air uniformly from air inletpipes surrounding the tubular body against the tubular body maintainedin the swelled state the film is cooled uniformly. The tubular body isthen guided for engaging the occludent means.

The bag material which is now flat and maintaining its occluded statecan be finished into individual bags by cutting followed by sealing thecut edges. In actual practice, however, owing to the necessity ofaccomplishing printing of such as trademarks, tradenames, etc. on thebag surface, the bag material that has been formed in a flat andcontinuous state, as described hereinabove, is first wound up on a reel,transferred to the printing step where after printing it is rewound onthe reel and thereafter cut and the cut edges simultaneously sealed.

The mode of practicing the invention will be described concretely belowwith reference to the accompanying drawings, in which:

FIG. 1 is a detailed front elevation of that section of a mechanismwhich continuously molds the bag material;

FIG. 2 is a top plan view of a mold section for making the bag material;

FIG. 3 is a cross-sectional view of the bag material taken along linesIIIIII of FIG. 1;

FIG. 4 is a top plan view showing the bag material subsequent to itshaving been occluded;

FIG. 5 is a top plan view showing separate bags formed on a conveyorbelt after having been cut from the tube material and cross sealed;

FIG. 6 is an enlarged view in section of the resultant synthetic resinbag;

FIG. 7 is an enlarged view in section showing a modification of theoccluding ribs;

FIG. 8 is a cross-sectional view showing the bag material in which twosets of occluding ribs have been formed;

Patented Dec. 13, 1966 FIG. 9 is a cross-sectional view similar to FIG.8 but showing the bag material in its flattened form, and line 0-0designating the location where it is to be cut longitudinally of thetube; and

FIG. 10 is an enlarged detailed fragmentary sectional view of theinterlocking occludent means.

As shown in FIGURES l and 2 an outer mold 1 has a core 3 with a shapednarrow annular extrusion gap 2 the'rebetween. Plastic is forced throughthe gap 2 by extruder mechanism not shown, and air introduced into atube extruded through the gap 2 through a pipe 4. As illustrated the gapis preferably of uniform width to form a tube of film of uniformthickness. There are formed molding grooves 7 and 8 in the outer surfaceof the core 3 communicating with the extrusion gap 2 for forming maleand female ribs 9 and 10 integrally with the bag body 6.

Directly above this mold (FIG. 1) there is provided a pair of deliveryrolls 11, 11 disposed in lateral fashion facing each other for claspingand delivering in a flat state the tubular bag body 6 that is extrudedfrom the mold. Air is blown in small amounts into the tubular bag body 6from the bottom through the aforesaid air inlet pipe 4-, with the toppart of the bag body 6 being held together by means of the deliveryrolls 11, 11. The bag body 6 is swelled or inflated and maintained in atubular shape. Below the rolls 11, 11 there is provided a pair of guideplates 12, 12 facing each other in roof fashion whereby the shoulderportion of the bag body 6 swelled into a tubular shape is guided and isgradually pressed flat as shown in FIG. 1 and passes between the rolls11, 11.

At that part of the apparatus where the tubular bag body 6 ascends, acold air discharge section, not shown, is provided. Air is appropriatelysupplied and is blown against the outer surface of the bag body 6 toremove heat from the freshly molded film and thus cool the same.

The interlocking elements 9 and 10 are aligned and interlocked to holdthe opposed sides of tube material together. The bag body 6 is thusmolded into a flat beltlike shape. In actual practice, however, since inmost cases printing of such as trademarks, tradenames, etc. areaccomplished, it is perhaps convenient to first wind up the bag materialin this state by guiding the same to a windup reel.

In the hereinabove-described apparatus, the cross-sectional shape of themale and female ribs suitable for occlusion of the bag body 6 can beobtained by suitably designing the configuration of the molding grooves7, 8. The cross-sectional shape of these male and female elements 9, 10may be suitably determined in accordance with the uses to which the bagsare to be put. For example, as shown in FIG. 7, for a container to beused for fine powders the ribs may be so formed so that the labialsection of the female rib 9 is turned inward along the length of the ribwhile the male rib 10 is formed arrowhead shaped. In addition,regardless of the shapes of the male and female ribs, when two setsthereof are formed facing each other, as illustrated in FIG. 8, andsubsequently cut along line 00 midway between the two when the bag bodyhas been flattened as in FIG. 9, two bags are obtainable at the sametime. FIG. 10 shows the rib and groove elements 9 and 10 in greaterdetail.

As shown in the drawings the male and female elements of each setthereof are spaced apart from each other in both circumferentialdirections or, in other words, are spaced apart from each other in bothdirections relative to the tube circumference. For example, in FIG- URE3 the male element 10 is spaced from the female element 9 in a clockwisedirection from element 10 around the circumference of the tube as wellas in a counterclockwise direction.

The incisions 7 and 8, which constitute a set of the molding grooves areincised in a part of the circumference of the core 3 with the shape ofthe grooves being of a wide variety. Since their positions will be determined by the size of the mold, by providing molding plates for the coreof the same size having a wide variety of incisions and selectivelyusing the same, it becomes possible to form ribs of any desired shape.

The bag body that has been molded as described hereinbefore is thenprocessed further in the following manner. First, the male and femaleribs that have been formed integrally in the bag body are occluded, thenafter flattening, to the surface of the bag body is imparted, ifrequired, the desired printing and thereafter by using an apparatus tobe described hereinafter the bag body is cut into the individual bag andsimultaneously therewith the cut edges of the bags are heat sealed.

In a position forward of a belt 203, rollers 207, 208 are disposedlongitudinally, around which an endless conveyor belt 209 is mounted.The tip of the bag body 6 which is delivered forth, FIGURE 5, is made tobe transferred s-moothly'from the belt 203 to the radially moving partof the conveyor belt 209. The surface of this conveyor belt 209 has alayer such as silicon rubber so that the bag body does not stick to thesurface of the conveyor belt as a result of operations such as cuttingand heat sealing. In addition, by suitable determination of the rotatingspeed of the rollers 207, 208, the rate of travel of the conveyor belt209 is made to be greater than that of the bag body 6. Anelectro-thermic means is provided, which makes possible simultaneouslywith the cutting of the bag body the heat sealing of the cut edges. Apressure plate 226 is provided. The individual bags are severed andsealed as shown in the copending application Serial 89,540. Further, at237 is a set of superposed belts that have been provided forward of theconveyor belt 209 and have been provided for the purpose of removing thebags that have been conveyed by the conveyor belt 209.

When the continuous tube is cut into predetermined widths starting atone end and the cut edges thereof are heat sealed, as a result of thefact that a unit width of a bag body leaves the bag body material and isplaced independently upon the top of the conveyor belt 209, the cutedges become spaced apart automatically from each other for an Sdistance.

In using these bags, by cutting the bags at the top 1, FIG. 6, andopening up the engagement of the male and female ribs, the bag is readyto be filled with whatever it is to be filled with. After the bags arefilled the male and remale ribs 9, 10 are again occluded, and ifnecessary, the mouth which was opened by cutting may be again sealedusing a heat sealer.

While the invention has been described with particular reference tospecific embodiments, it is to be understood that it is not to belimited thereto, but that changes may be made therein without departingfrom the scope of the invention which is defined in the appended claims.

I claim:

1. A structure for a reclosable container comprising,

a flexible closed integral one-piece tube of a flexible plastic film,

cross-seals at the ends of said tube forming a closed first and secondinterlocking elements integral with and one piece with the tube on theinner surface thereof shaped for cooperative pressure engagement and forforcible separation,

said elements spaced apart from each other in both circumferentialdirections,

said film including a body forming sheet portion between theinterlocking elements at one side of the first element for forming thebody of the bag,

and said film including a flange forming sheet portion between theinterlocking elements at the other side of said first element with saidflange portion extending over the top of the bag and adapted to besevered for access to the bag and providing separate opening grippingflanges for the elements.

2. A structure for a reclosable container comprising,

a flexible closed integral one-piece tube of a flexible plastic filmwith the axis of the tube extending laterally of a bag formed from thetube and the circumference of the tube extending to form the front andback of the bag,

cross-seals at the ends of said tube forming sides for the bag,

first and second interlocking elements integral with and of one piecewith the tube on the inner surface thereof with the ends of saidelements extending to the sides of the bag and being shaped forcooperative pressure interlocking engagement and for forcibleseparation,

said elements spaced apart from each other in both directions relativeto the tube circumference, said film including a body forming sheetportion between the interlocking elements extending downwardly at oneside of the first element to the second element for forming the body ofthe bag, and said film including a flange forming sheet portion betweenthe interlocking elements extending upwardly at the other side of saidfirst element to the second element with said flange portion extendingover the top of the bag and adapted to be severed for access to the bagand providing separate opening gripping flanges for the elements.

3. A structure for a reclosable container in accordance with claim 2wherein said first interlocking element is arrowhead shaped incross-section and said second interlocking element is substantiallycomplementary shaped to form a groove to embrace and interlock with saidfirst element.

4. A structure for a reclosable container in accordance with claim 2wherein said flexible plastic film is of substantially uniform thicknessfor said flange portion and for said body portion.

5. A structure for a reclosable container in accordance with claim 2wherein said cross-seals are formed by heat and weld the film at theends of the tube together.

6. A structure for a reclosable container in accordance with claim 2wherein said first and second elements are normally interlocked beforesevering said flange portion to provide the separate gripping flanges.

References Cited by the Examiner UNITED STATES PATENTS 2,674,289 4/ 1954Silverman -3 2,878,849 3/1959 Lingenfelter et al 150-3 2,916,197 12/1959Detrie et al 20647 X FOREIGN PATENTS 1,031,136 3/1953 France.

284,060 11/1952 Switzerland.

FRANKLIN T. GARRETT, Primary Examiner. JOSEPH R. LECLAIR, Examiner. M.L. MINSK, Assistant Examiner.

1. A STRUCTURE FOR A RECLOSABLE CONTAINER COMPRISING, A FLEXIBLE CLOSEDINTEGRAL ONE-PIECE TUBE OF A FLEXIBLE PLASTIC FILM, CROSS-SEALS AT THEENDS OF SAID TUBE FORMING A CLOSED BAG, FIRST AND SECOND INTERLOCKINGELEMENTS INTEGRAL WITH AND ONE PIECE WITH THE TUBE ON THE INNER SURFACETHEREOF SHAPED FOR COOPERATIVE PRESSURE ENGAGEMENT AND FOR FORCIBLESEPARATION, SAID ELEMENTS SPACED APART FROM EACH OTHER IN BOTHCIRCUMFERENTIAL DIRECTIONS. SAID FILM INCLUDING A BODY FORMING SHEETPORTIN BETWEEN THE INTERLOCKING ELEMENTS AT ONE SIDE OF THE FIRSTELEMENT FOR FORMING THE BODY OF THE BAG, AND SAID FILM INCLUDING AFLANGE FORMING SHEET PORTION BETWEEN THE INTERLOCKING ELEMENTS AT THEOTHER SIDE OF SAID FIRST ELEMENT WITH SAID FLANGE PORTION EXTENDING OVERTHE TOP OF THE BAG AND ADAPTED TO BE SEVERED FOR ACCESS TO THE BAG ANDPROVIDING SEPARATE OPENING GRIPPING FLANGES FOR THE ELEMENTS.